California represents approximately 12 billion gallons a day of the 65 billion gallons a day of fresh groundwater used daily in the United States. Groundwater is found in water-bearing layers of saturated underground rock and sand, called aquifers, which are formed as surface water percolates through layers of earth and fills porous rock and sand. Groundwater moves slowly compared to surface water, and are recharged naturally through precipitation that filters through a recharge area. The recharge process is typically very slow, taking from months to years to centuries. If the withdrawal or pumping rate matches the recharge rate, the aquifer is a renewable resource; if the withdrawal rate exceeds recharge then the aquifer becomes a nonrenewable resource and we are said to be mining the groundwater. According to the Department of Water Resources (DWR), despite California’s heavy reliance on groundwater, basic information for many of the groundwater basins is lacking. Particular essential data necessary to provide for both the protection and optimal use of this resource is not available.
In California, in 1999,the State Legislature approved funding and directed the DWR to update the inventory of groundwater basins contained in Bulletin 118 (1975), California’s Ground Water and Bulletin 118-80 (1980), Ground Water Basins in California. In 2001, the California State Legislature passed AB 599, requiring the State Water Resources Control Board, SWRCB, to establish a comprehensive monitoring program to assess groundwater quality in each groundwater basin in the State and to increase coordination among agencies that collect groundwater contamination information.
Significant legislation was passed in 2000, 2001 and 2002. AB 303 authorizes grants to help local agencies develop better groundwater management strategies. AB 599 (2001) requires, for the first time, that the SWRCB, in cooperation with other agencies, develop a comprehensive monitoring program capable of assessing groundwater quality in every basin in the State with the intent of maintaining a safe groundwater supply. SB 610 (2001) and SB 901 (2001) together require urban water suppliers, in their urban water management plans, to determine the adequacy of current and future supplies to meet demands. Detailed groundwater information is required for those suppliers that use groundwater. SB 221 (2001) prohibits approval of certain housing developments without verification of an available water supply. Despite all this legislation it appears that limited progress has been made in developing an integrated groundwater plan because little hard data exists for the basins. Without information about the state’s water basins the reality of the situation can be ignored and the complex task of attempting to develop a workable plan of water resource management is impossible.
California’s climate is dominated by the Pacific storm track. The mountain ranges cause precipitation to fall mostly on the western slopes. These storms also leave tremendous accumulations of snow in the Sierra Nevada during the winter months. While the average annual precipitation in California is about 23inches (DWR 1998), the range of annual rainfall varies greatly from more than 140 inches in the northwestern part of the State to less than 4 inches in the southeastern part of the State. Snowmelt and rain falling in the mountains flows into creeks, streams, and rivers. As these flows make their way into the valleys, much of the water percolates into the ground. The vast majority of California’s accessible groundwater is stored in alluvial groundwater basins.
California’s natural hydrology is too limited to support significant growth in population, industry, and agriculture. Robert Glennon (Pinching Straws) described the natural condition of California’s Central Valley, as an American Serengeti, characterized by extensive grasslands during the summer, marshlands in the winter and spring. Not only is California relatively arid, but it is subject to, seasonal and climatic variability that threaten a reliable water supply. Approximately 70 percent of the State’s average annual rain and snowmelt runoff occurs north of Sacramento, while about 75 percent of the State’s urban and agricultural water needs are to the south. Most of the State’s precipitation falls between October and April with half of it occurring December through February in average years. Yet, the peak demand for this water occurs in the summer months. Climatic variability in the form of dramatic deviations from average supply conditions by droughts and flooding further complicate this. The result of this has been the development of an intricate system of reservoirs, canals, and pipelines under federal, State and local projects intended to change the nature of the stat’s hydrology. However, a significant portion of California’s water supply needs is met by groundwater. Typically, groundwater supplies about 30 percent of California’s urban and agricultural water needs.
The level of groundwater extraction necessary in even a typical year is unsustainable, it exceeds the recharge rate. In dry years, groundwater use increases to about 40 percent statewide and 60% or more in some regions. These are estimates because groundwater use is not measured, it is estimated. The true dependence on groundwater is only estimated. From these estimates, the land subsidence observed in the central valley and the drop in groundwater level, it appears that California is mining its groundwater, using more water than is recharged. It has been apparent for years that California has been mining its groundwater; however, when major groundwater basins begin to fail if California is true to form the public will be shocked because no preparations will have been made no plan voted on by the people. But California will keep on pumping until there is no longer any groundwater to pump. When the groundwater fails there will be a catastrophic reduction in water availability. The costal centers will survive on solar powered desalinization, but California as we know it will be gone.
California does not have a comprehensive monitoring network for evaluating the health of its groundwater resource, including quantity and quality of groundwater. The reason is primarily due to the cost involved in drilling and monitoring the vast area underground. Given that groundwater basins cover about 40 percent of the State’s area, the cost of a dedicated monitoring network would be astronomical and the state never found the money to gather data even during the “flush” years. The task is further complicated by the fact that, groundwater is a locally controlled resource. The twenty-seven groundwater management ordinances in the state are managed by local governments. California’s diversion and management of the available water has severely damaged many of the ecological zones of the state. Now the estuary and fishing industry of the Sacramento and San Pablo Delta is threatened and Fish and Wildlife Service have invoked the endangered species act to protect the estuary. The major problem here is quantity of available fresh water to maintain the ecological balance of the estuary.